Re: Basic question?What 's the key if there 's no FD(Functional Dependencies)?

From: Aloha Kakuikanu <aloha.kakuikanu_at_yahoo.com>
Date: 3 Nov 2006 18:48:52 -0800
Message-ID: <1162608532.686079.39340_at_f16g2000cwb.googlegroups.com>


NENASHI, Tegiri wrote:
> Aloha Kakuikanu wrote:
> > NENASHI, Tegiri wrote:
> > > Jan Hidders wrote:
> > > > Do you know of any results that might be interesting for database
> > > > theory and could not already be shown with good old set theory?
> > >
> > > The categorical sketches to use for universal view updatability:
> > >
> > > Michael Johnson and Robert Rosebrugh.
> > > Universal view updatability
> >
> > They claim to solve view updatability?
>
> No they claim to find out the universal property when the view can be
> updated. See the article.
>
> >
> OK, I have a table RealPeople
> > with one attribute Name and the view
> >
> > CDTPosters =
> > RealPeople
> > union
> > {(name=TeGiriNeNashi)}
> >
> > and a constraint
> >
> > RealPeople
> > intersect
> > {(name=TeGiriNeNashi)}
> > =
> > {}
> >
> > Is the CDTPosters view updatable?
> >
>
> In sketches the constraints are defined by diagram commutability. The
> view is not updatable because the diagram does not commute.

This conclusion is unsatisfactory. The view is updatable.

> > BTW, how is that lawsuit against the movie industry is going?
> > http://groups.google.com/group/alt.video.dvd.tech/browse_frm/thread/ec185c0b13e02f7e/b5537612074bd38d?lnk=st&q=&rnum=2&hl=en#b5537612074bd38d
>
> It is some confusion.

There is some confusion? Coincidence I'd say. Received on Sat Nov 04 2006 - 03:48:52 CET

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